The distribution of limb pain in decompression sickness.

BACKGROUND For many years there has been a widely held but largely unsubstantiated belief that pain in the upper limb in decompression sickness (DCS) is associated with bounce diving, whereas compressed air workers, saturation divers and high altitude aviators are more susceptible to involvement of the lower limbs. HYPOTHESIS The hypothesis of counter current exchange of inert gas, modulated by changes in tissue temperature, has been evaluated as a possible mechanism to explain the reported distribution of limb pain in DCS. METHODS An extensive review of over 19,000 cases of limb pain decompression illness has been undertaken from case reports stored in the diving accident database at the Institute of Naval Medicine, in the published literature, and from unpublished clinical and experimental reports. RESULTS There was a predominance of upper limb involvement in bounce divers and, in contrast to traditional teaching, in aviators. By contrast, the lower limbs were more commonly involved in compressed air workers and saturation divers. CONCLUSION Each of the occupational exposures has been discussed individually with reference to counter-current exchange and other factors as potential influences on the distribution of disease. We conclude that counter-current exchange of inert gas may be implicated in the distribution of limb pain in DCS.